Machine function v Skill Level

  1. Wallace

    Wallace Member

    Messages:
    7,168
    Location:
    Staines, Middlesex, England.

    The modern Oxford machines or the older oil filled arc welders?
     
  2. matt1978

    matt1978 www.lorch.eu

    Messages:
    3,742
    Location:
    UK, Cannock
    Some of the Oxford machines are conventional Transformer rectifiers. Some are Thyristor Controlled.
     
  3. kaiser Member

    Messages:
    15
    South Africa
    Firstly your weld is fine! But i get exactly where you come from, and yes, there is a big difference between a good machine and a cheap one. A BIG difference!
    The most obvious differences are the controls, the wire feed motor and also, for transformer based machines, whether or not it is a single or three phase machine. For inverters, this last point is irrelevant.
    So in general terms. If you have a single phase machine, the rectification of the AC input leaves a lot to be desired, although it can be improved by a few technical tricks. Here a three phase machine will give naturally a smoother weld, because you have three overlapping sine curves, and their rectification is easier and smoother, everything else the same. Then the wire feed motor. Cheap machines have motors the size of your thumb. You can hear them, they whine away. Generally I would not buy a machine where you can hear the wire feed motor. The control board can also be iffy, and cheap ones can get components that heat up and drift, making it impossible to keep a set speed.
    So, if you have to buy a welder, go for the heaviest machine, especially if it is a transformer model. Go for good earth clamps, heavy and long supply cords, look at the wheels, the torch and look at the steel casing (they like to skimp on the quality on all these issues here).
    If you go for an inverter, they do weld better, but for good transformer machines, there is not much in it, and the transformer machines last much better, are far more forgiving ito supply nasties and, if you are unlucky, are far easier to repair, even if the machine is off the market and the supplier nowhere to be found. Go by your instincts.
    And yes, you owe it to yourself to go and get a better welding machine. Your weld is fine, but you will appreciate the difference, and you will also be able to enjoy it. And don't be afraid of an old transformer machine! They are easy to get on track, and keep there. And they respond beautifully to cleaning of contactors, fans, electrical joints and general attention and cleaning. Best if you could get a copper wound transformer. Aluminium is OK, but tend to form rust where it bolts together, typically on the rectifier and near the output to torch and earth. Tat impedes current flow, increases temperature and creates more aluminium oxide (rust) I would happily buy an old transformer machine and give it some love. They are like puppies, they will never forget a good deed! And they will stay with you, come hell and high water!
    And use a mixed gas for better results. CO2 is cheap, and the results are more rough and spattery.
    So start a scan for an old machine! You will never regret it!
     
    mechman likes this.
  4. kaiser Member

    Messages:
    15
    South Africa
    Thanks to both!
    Well arc welders are also of interest, although I was mainly thinking of MIG/MAG.
    I have read up on the Oxford MIG machines. They seem to make powerful machines that exceeds what others do, in single phase. As I understand it, they are talking about special controls, that allow them to get higher efficiencies and thus make bigger machines in single phase. The biggest machines I can recall were the old style grey SIP Ideal 240AMP and 240S (copper wound) which were very good units. Later they introduced the red more square 300Amp MigMate Industrial, which I believe in essence was the same machine, but with smaller wire feed motors. Inflation in numbers??
    I have never heard or seen anything bigger than that, but Oxford are talking much bigger stuff in single phase.
    Now how do they do that? and how does it work? are they really as powerful as a 3 or 400 machine in three phase?
    and generally the quality, how do they weld, what are people saying? What what what??:laughing:
     
    Wallace likes this.
  5. tom2207 Member

    Messages:
    1,796
    Location:
    uk northern ireland
    drop them a mail , and ask ,, Im sure they will be glad to chat to you.
     
  6. matt1978

    matt1978 www.lorch.eu

    Messages:
    3,742
    Location:
    UK, Cannock
    It’s conventional Transformer technology. As with any welding machine, especially Transformer based machines you can only get out what you put in, they make very large output 1ph 230v Transformer machines because in the UK and Ireland it is possible to draw a much much higher current on a 230v supply compared to the rest of continental Europe. Over 100 amps is not unheard of, but 32 and 64 amp supply’s are common place especially on farms.
     
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  7. kaiser Member

    Messages:
    15
    South Africa
    Yes, I know, I can do that and I might just do that, too, but sometimes it is good to get the feeling of the end users. If I write to Jaguar, they will tell me all they want me to know! If I speak to the owners, they will tell me all I need to know.
     
    mechman likes this.
  8. Munkul

    Munkul Member

    Messages:
    2,399
    Cumbria, UK
    Amps are amps, but... if you have a lower voltage supply, then you need more amps in to give same amps out.
    BUT
    I might be wrong on this, its just a personal opinion shared by quite a few people... when it comes to MIG, then IN GENERAL, a 3 phase machine is smoother. It takes less rectifying and smoothing the current, for one. But also, in general, 3 phase machines tend to be made bigger and better than single phase... what's better, a 200 amp machine at 200 amps, or a 300 amp machine at 200 amps?...
    There are exceptions to this, I've seen pretty poor 3 phase machines and some truly excellent 1phase machines. But if you want more than 200 amps, then 3phase makes it a lot easier to find a machine.

    The OP suffered a common misconception when he bought a 140 amp MIG to do the work that a stick welder at 140 amps can do. Unfortunately it doesn't work like that when you get to thicker metal, its too easy to make a weld with poor fusion.
     
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  9. metalmelt Member

    Messages:
    253
    Location:
    UK
    Current Oxford machines are made in York by a company called Technical Arc and they also make other welders and I think another is Easi Weld or something similar and they are made to order. They use transformers and mofset/capacitors to give an inbetween and this is something the more rugged American welders use as they claim it is less efficient than invertors but more efficient then pure transformer.
     
  10. matt1978

    matt1978 www.lorch.eu

    Messages:
    3,742
    Location:
    UK, Cannock
    That’s not quite correct. Only a small portion of the Oxford range is a “Chopper” style machine. The Hybrid machines (eg multi process) machines are Choppers, which is Transformer/Thyrister. This is old technology. Not saying there is anything wrong with it, Lorch and many other manufacturers had Thyristor controlled “Chopper” machines in the late 80’s early 90’s. They do indeed have benefits, but also some drawbacks. The weight is considerably heavier than an it’s inverter counterparts and they are not as good performance wise at the low end with Mig.

    However the largest part of the Oxford Machine range is conventional Transformer/Rectifier technology.

    But I am sure for some people they are a very welcome and this is certainly not an post to knock Chopper machines.

    https://www.oxfordwelders.co.uk/

    You can read this for yourself here. They are indeed made by Technical Arc and they also make lots of other brands such as Portamig and Britweld
     
  11. minimutly Member

    Messages:
    1,220
    Location:
    Pembrokeshire Wales
    You won't need to wait long before having the chance to buy a new welder - Sealey stuff tends to just outlast the guarantee - so you're allready on a winner. Get a 200A machine next time.
     
  12. metalmelt Member

    Messages:
    253
    Location:
    UK
    To avoid any confusion Matt I was referring to transformer machines as most manufacturers have invertors in their line up and the thread drifted to transformer machines.

    Britweld, that was the one I was thinking of.
     
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